1. Field of the Invention
The present invention relates to a seal structure to be used in conjunction with a rotary shaft journaled from and projecting outwardly through an opening formed in a housing portion. The seal structure is operative to prevent solid contaminants as well as fluid contaminants from reaching a shaft bearing inwardly of the seal structure. Further, the seal structure also serves to prevent the loss of liquids within the housing portion inwardly of the seal structure to the outside environment.
2. Description of Related Art
Many varied designs of devices have been manufactured to prevent the loss of lubricant from bearing housings. The loss of lubricant leads to premature bearing failure and the most common devices used to prevent lubricant loss are termed "lip seals" of various styles.
As the lip of these seals is in contact with the rotating shaft, wear occurs on both the shaft and the lip. This allows lubricant to be lost and, in addition, allows outside contaminants to enter the bearing housing. These contaminants lead to premature bearing failure.
Many industries would prefer to replace these lip seals with some other type of seal which does not wear out as quickly as a lip seal.
Several types of devices have been manufactured by different manufacturers. Some of these devices work fairly well in preventing entry of contaminants as long as the shaft is rotating, thus centrifugal force is a key requirement for these types of designs. Inasmuch as most equipment does not operate 24 hours each day for 365 days of the year, few, if any, previous designs actually prevent entry of contaminants when the equipment has been shutdown and remains idle for any period of time.
Also, only a few of the previous designs of seals actually prevent loss of lubricant.
Many of the lip seals and other previous designed devices are installed in equipment (such as certain types of pumps) wherein the equipment is occasionally shutdown, and the associated shaft is adjusted axially to compensate for wear of some components such as an impeller. Many of these previous design devices are installed as two or more parts, and these parts will separate when the shaft is adjusted axially (or if the shaft moves axially due to changing thrust loads on the equipment).
Many of the previous designs of seals rely solely upon a basic labyrinth seal to be formed with the rotating shaft. Under sized shafts cause the labyrinth clearance to exceed this design tolerance, resulting in leakage proportional to the amount of excess clearance.
The main object of this invention is to provide a bearing protector type of seal which provides means to prevent entry of contaminants into the housing both when the shaft is rotating and the when the shaft is not rotating.
A further important object of this invention to provide a shaft bearing seal which also will be operative to prevent loss of lubricant or other liquids from within the housing when the associated shaft is rotating and also when the associated shaft is stationary.
Yet another very important object of this invention is to provide a shaft seal in accordance with the preceding objects and which also will be effective to maintain the desired seal even though the associated shaft shifts axially relative to the associated housing portion from which the seal is supported.
A final object of this invention to be specifically enumerated herein is to provide a shaft seal in accordance with the preceding objects and which will conform to conventional forms manufacture, be of simple construction and easy to use so as to provide a device that will be economically feasible, long-lasting and relatively trouble free in operation.
These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout.